// Copyright (c) Umbraco.
// See LICENSE for more details.

using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using System.Text;
using System.Text.RegularExpressions;
using Umbraco.Cms.Core;
using Umbraco.Cms.Core.Strings;

namespace Umbraco.Extensions;

/// <summary>
///     String extension methods
/// </summary>
public static class StringExtensions
{
    internal static readonly Lazy<Regex> Whitespace = new(() => new Regex(@"\s+", RegexOptions.Compiled));

    private const char DefaultEscapedStringEscapeChar = '\\';
    private static readonly char[] ToCSharpHexDigitLower = "0123456789abcdef".ToCharArray();
    private static readonly char[] ToCSharpEscapeChars;
    internal static readonly string[] JsonEmpties = { "[]", "{}" };

    /// <summary>
    ///     The namespace for URLs (from RFC 4122, Appendix C).
    ///     See <a href="http://www.ietf.org/rfc/rfc4122.txt">RFC 4122</a>
    /// </summary>
    internal static readonly Guid UrlNamespace = new("6ba7b811-9dad-11d1-80b4-00c04fd430c8");

    private static readonly char[] CleanForXssChars = "*?(){}[];:%<>/\\|&'\"".ToCharArray();

    // From: http://stackoverflow.com/a/961504/5018
    // filters control characters but allows only properly-formed surrogate sequences
    private static readonly Lazy<Regex> InvalidXmlChars = new(() =>
        new Regex(
            @"(?<![\uD800-\uDBFF])[\uDC00-\uDFFF]|[\uD800-\uDBFF](?![\uDC00-\uDFFF])|[\x00-\x08\x0B\x0C\x0E-\x1F\x7F-\x9F\uFEFF\uFFFE\uFFFF]",
            RegexOptions.Compiled));

    static StringExtensions()
    {
        var escapes = new[] { "\aa", "\bb", "\ff", "\nn", "\rr", "\tt", "\vv", "\"\"", "\\\\", "??", "\00" };
        ToCSharpEscapeChars = new char[escapes.Max(e => e[0]) + 1];
        foreach (var escape in escapes)
        {
            ToCSharpEscapeChars[escape[0]] = escape[1];
        }
    }

    /// <summary>
    ///     Convert a path to node ids in the order from right to left (deepest to shallowest)
    /// </summary>
    /// <param name="path"></param>
    /// <returns></returns>
    public static int[] GetIdsFromPathReversed(this string path)
    {
        ReadOnlySpan<char> pathSpan = path.AsSpan();
        List<int> nodeIds = [];
        foreach (Range rangeOfPathSegment in pathSpan.Split(Constants.CharArrays.Comma))
        {
            if (int.TryParse(pathSpan[rangeOfPathSegment], NumberStyles.Integer, CultureInfo.InvariantCulture, out int pathSegment))
            {
                nodeIds.Add(pathSegment);
            }
        }

        var result = new int[nodeIds.Count];
        var resultIndex = 0;
        for (int i = nodeIds.Count - 1; i >= 0; i--)
        {
            result[resultIndex++] = nodeIds[i];
        }

        return result;
    }

    /// <summary>
    ///     Removes new lines and tabs
    /// </summary>
    /// <param name="txt"></param>
    /// <returns></returns>
    public static string StripWhitespace(this string txt) => Regex.Replace(txt, @"\s", string.Empty);

    public static string StripFileExtension(this string fileName)
    {
        // filenames cannot contain line breaks
        if (fileName.Contains('\n') || fileName.Contains('\r'))
        {
            return fileName;
        }

        ReadOnlySpan<char> spanFileName = fileName.AsSpan();
        var lastIndex = spanFileName.LastIndexOf('.');
        if (lastIndex > 0)
        {
            ReadOnlySpan<char> ext = spanFileName[lastIndex..];

            // file extensions cannot contain whitespace
            if (ext.Contains(' '))
            {
                return fileName;
            }

            return new string(spanFileName[..lastIndex]);
        }

        return fileName;
    }

    /// <summary>
    ///     Determines the extension of the path or URL
    /// </summary>
    /// <param name="file"></param>
    /// <returns>Extension of the file</returns>
    public static string GetFileExtension(this string file)
    {
        // Find any characters between the last . and the start of a query string or the end of the string
        const string pattern = @"(?<extension>\.[^\.\?]+)(\?.*|$)";
        Match match = Regex.Match(file, pattern);
        return match.Success
            ? match.Groups["extension"].Value
            : string.Empty;
    }

    /// <summary>
    ///     This tries to detect a json string, this is not a fail safe way but it is quicker than doing
    ///     a try/catch when deserializing when it is not json.
    /// </summary>
    /// <param name="input"></param>
    /// <returns></returns>
    public static bool DetectIsJson(this string input)
    {
        if (input.IsNullOrWhiteSpace())
        {
            return false;
        }

        input = input.Trim();
        return (input[0] is '[' && input[^1] is ']') || (input[0] is '{' && input[^1] is '}');
    }

    public static bool DetectIsEmptyJson(this string input) =>
        JsonEmpties.Contains(Whitespace.Value.Replace(input, string.Empty));

    public static string ReplaceNonAlphanumericChars(this string input, string replacement)
    {
        // any character that is not alphanumeric, convert to a hyphen
        var mName = input;
        foreach (var c in mName.ToCharArray().Where(c => !char.IsLetterOrDigit(c)))
        {
            mName = mName.Replace(c.ToString(CultureInfo.InvariantCulture), replacement);
        }

        return mName;
    }

    public static string ReplaceNonAlphanumericChars(this string input, char replacement)
    {
        var chars = input.ToCharArray();
        for (var i = 0; i < chars.Length; i++)
        {
            if (!char.IsLetterOrDigit(chars[i]))
            {
                chars[i] = replacement;
            }
        }

        return new string(chars);
    }

    /// <summary>
    ///     Cleans string to aid in preventing xss attacks.
    /// </summary>
    /// <param name="input"></param>
    /// <param name="ignoreFromClean"></param>
    /// <returns></returns>
    public static string CleanForXss(this string input, params char[] ignoreFromClean)
    {
        // remove any HTML
        input = input.StripHtml();

        // strip out any potential chars involved with XSS
        return input.ExceptChars(new HashSet<char>(CleanForXssChars.Except(ignoreFromClean)));
    }

    public static string ExceptChars(this string str, HashSet<char> toExclude)
    {
        var sb = new StringBuilder(str.Length);
        foreach (var c in str.Where(c => toExclude.Contains(c) == false))
        {
            sb.Append(c);
        }

        return sb.ToString();
    }

    /// <summary>
    ///     This will append the query string to the URL
    /// </summary>
    /// <param name="url"></param>
    /// <param name="queryStrings"></param>
    /// <returns></returns>
    /// <remarks>
    ///     This methods ensures that the resulting URL is structured correctly, that there's only one '?' and that things are
    ///     delimited properly with '&amp;'
    /// </remarks>
    public static string AppendQueryStringToUrl(this string url, params string[] queryStrings)
    {
        // remove any prefixed '&' or '?'
        for (var i = 0; i < queryStrings.Length; i++)
        {
            queryStrings[i] = queryStrings[i].TrimStart(Constants.CharArrays.QuestionMarkAmpersand)
                .TrimEnd(Constants.CharArrays.Ampersand);
        }

        var nonEmpty = queryStrings.Where(x => !x.IsNullOrWhiteSpace()).ToArray();

        if (url.Contains('?'))
        {
            return url + string.Join("&", nonEmpty).EnsureStartsWith('&');
        }

        return url + string.Join("&", nonEmpty).EnsureStartsWith('?');
    }

    /// <summary>
    ///     Returns a stream from a string
    /// </summary>
    /// <param name="s"></param>
    /// <returns></returns>
    internal static Stream GenerateStreamFromString(this string s)
    {
        var stream = new MemoryStream();
        var writer = new StreamWriter(stream);
        writer.Write(s);
        writer.Flush();
        stream.Position = 0;
        return stream;
    }

    // this is from SqlMetal and just makes it a bit of fun to allow pluralization
    public static string MakePluralName(this string name)
    {
        if (name.EndsWith("x", StringComparison.OrdinalIgnoreCase) ||
            name.EndsWith("ch", StringComparison.OrdinalIgnoreCase) ||
            name.EndsWith("s", StringComparison.OrdinalIgnoreCase) ||
            name.EndsWith("sh", StringComparison.OrdinalIgnoreCase))
        {
            name += "es";
            return name;
        }

        if (name.EndsWith("y", StringComparison.OrdinalIgnoreCase) && name.Length > 1 &&
            !IsVowel(name[^2]))
        {
            name = name.Remove(name.Length - 1, 1);
            name += "ies";
            return name;
        }

        if (!name.EndsWith("s", StringComparison.OrdinalIgnoreCase))
        {
            name += "s";
        }

        return name;
    }

    public static bool IsVowel(this char c)
    {
        switch (c)
        {
            case 'O':
            case 'U':
            case 'Y':
            case 'A':
            case 'E':
            case 'I':
            case 'o':
            case 'u':
            case 'y':
            case 'a':
            case 'e':
            case 'i':
                return true;
        }

        return false;
    }

    /// <summary>
    ///     Trims the specified value from a string; accepts a string input whereas the in-built implementation only accepts
    ///     char or char[].
    /// </summary>
    /// <param name="value">The value.</param>
    /// <param name="forRemoving">For removing.</param>
    /// <returns></returns>
    public static string Trim(this string value, string forRemoving)
    {
        if (string.IsNullOrEmpty(value))
        {
            return value;
        }

        return value.TrimEnd(forRemoving).TrimStart(forRemoving);
    }

    public static string EncodeJsString(this string s)
    {
        var sb = new StringBuilder();
        foreach (var c in s)
        {
            switch (c)
            {
                case '\"':
                    sb.Append("\\\"");
                    break;
                case '\\':
                    sb.Append("\\\\");
                    break;
                case '\b':
                    sb.Append("\\b");
                    break;
                case '\f':
                    sb.Append("\\f");
                    break;
                case '\n':
                    sb.Append("\\n");
                    break;
                case '\r':
                    sb.Append("\\r");
                    break;
                case '\t':
                    sb.Append("\\t");
                    break;
                default:
                    int i = c;
                    if (i < 32 || i > 127)
                    {
                        sb.AppendFormat("\\u{0:X04}", i);
                    }
                    else
                    {
                        sb.Append(c);
                    }

                    break;
            }
        }

        return sb.ToString();
    }

    public static string TrimEnd(this string value, string forRemoving)
    {
        if (string.IsNullOrEmpty(value))
        {
            return value;
        }

        if (string.IsNullOrEmpty(forRemoving))
        {
            return value;
        }

        while (value.EndsWith(forRemoving, StringComparison.InvariantCultureIgnoreCase))
        {
            value = value.Remove(value.LastIndexOf(forRemoving, StringComparison.InvariantCultureIgnoreCase));
        }

        return value;
    }

    public static string TrimStart(this string value, string forRemoving)
    {
        if (string.IsNullOrEmpty(value))
        {
            return value;
        }

        if (string.IsNullOrEmpty(forRemoving))
        {
            return value;
        }

        while (value.StartsWith(forRemoving, StringComparison.InvariantCultureIgnoreCase))
        {
            value = value[forRemoving.Length..];
        }

        return value;
    }

    public static string EnsureStartsWith(this string input, string toStartWith)
    {
        if (input.StartsWith(toStartWith))
        {
            return input;
        }

        return toStartWith + input.TrimStart(toStartWith);
    }

    public static string EnsureStartsWith(this string input, char value) =>
        input.StartsWith(value.ToString(CultureInfo.InvariantCulture)) ? input : value + input;

    public static string EnsureEndsWith(this string input, char value) =>
        input.EndsWith(value.ToString(CultureInfo.InvariantCulture)) ? input : input + value;

    public static string EnsureEndsWith(this string input, string toEndWith) =>
        input.EndsWith(toEndWith.ToString(CultureInfo.InvariantCulture)) ? input : input + toEndWith;

    public static bool IsLowerCase(this char ch) => ch.ToString(CultureInfo.InvariantCulture) ==
                                                    ch.ToString(CultureInfo.InvariantCulture).ToLowerInvariant();

    public static bool IsUpperCase(this char ch) => ch.ToString(CultureInfo.InvariantCulture) ==
                                                    ch.ToString(CultureInfo.InvariantCulture).ToUpperInvariant();

    /// <summary>
    ///     Indicates whether a specified string is null, empty, or
    ///     consists only of white-space characters.
    /// </summary>
    /// <param name="value">The value to check.</param>
    /// <returns>
    ///     Returns <see langword="true" /> if the value is null,
    ///     empty, or consists only of white-space characters, otherwise
    ///     returns <see langword="false" />.
    /// </returns>
    public static bool IsNullOrWhiteSpace([NotNullWhen(false)] this string? value) => string.IsNullOrWhiteSpace(value);

    [return: NotNullIfNotNull("defaultValue")]
    public static string? IfNullOrWhiteSpace(this string? str, string? defaultValue) =>
        str.IsNullOrWhiteSpace() ? defaultValue : str;

    /// <summary>The to delimited list.</summary>
    /// <param name="list">The list.</param>
    /// <param name="delimiter">The delimiter.</param>
    /// <returns>the list</returns>
    [SuppressMessage("Microsoft.Design", "CA1026:DefaultParametersShouldNotBeUsed", Justification = "By design")]
    public static IList<string> ToDelimitedList(this string list, string delimiter = ",")
    {
        var delimiters = new[] { delimiter };
        return !list.IsNullOrWhiteSpace()
            ? list.Split(delimiters, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
                .ToList()
            : new List<string>();
    }

    /// <summary>enum try parse.</summary>
    /// <param name="strType">The str type.</param>
    /// <param name="ignoreCase">The ignore case.</param>
    /// <param name="result">The result.</param>
    /// <typeparam name="T">The type</typeparam>
    /// <returns>The enum try parse.</returns>
    [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes", Justification = "By Design")]
    [SuppressMessage("Microsoft.Design", "CA1021:AvoidOutParameters", MessageId = "2#", Justification = "By Design")]
    public static bool EnumTryParse<T>(this string strType, bool ignoreCase, out T? result)
    {
        try
        {
            result = (T)Enum.Parse(typeof(T), strType, ignoreCase);
            return true;
        }
        catch
        {
            result = default;
            return false;
        }
    }

    /// <summary>
    ///     Parse string to Enum
    /// </summary>
    /// <typeparam name="T">The enum type</typeparam>
    /// <param name="strType">The string to parse</param>
    /// <param name="ignoreCase">The ignore case</param>
    /// <returns>The parsed enum</returns>
    [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes", Justification = "By Design")]
    [SuppressMessage("Microsoft.Design", "CA1021:AvoidOutParameters", MessageId = "2#", Justification = "By Design")]
    public static T EnumParse<T>(this string strType, bool ignoreCase) => (T)Enum.Parse(typeof(T), strType, ignoreCase);

    /// <summary>
    ///     Strips all HTML from a string.
    /// </summary>
    /// <param name="text">The text.</param>
    /// <returns>Returns the string without any HTML tags.</returns>
    public static string StripHtml(this string text)
    {
        const string pattern = @"<(.|\n)*?>";
        return Regex.Replace(text, pattern, string.Empty, RegexOptions.Compiled);
    }

    /// <summary>
    ///     Encodes as GUID.
    /// </summary>
    /// <param name="input">The input.</param>
    /// <returns></returns>
    public static Guid EncodeAsGuid(this string input)
    {
        if (string.IsNullOrWhiteSpace(input))
        {
            throw new ArgumentNullException("input");
        }

        var convertToHex = input.ConvertToHex();
        var hexLength = convertToHex.Length < 32 ? convertToHex.Length : 32;
        var hex = convertToHex[..hexLength].PadLeft(32, '0');
        Guid output = Guid.Empty;
        return Guid.TryParse(hex, out output) ? output : Guid.Empty;
    }

    /// <summary>
    ///     Converts to hex.
    /// </summary>
    /// <param name="input">The input.</param>
    /// <returns></returns>
    public static string ConvertToHex(this string input)
    {
        if (string.IsNullOrEmpty(input))
        {
            return string.Empty;
        }

        var sb = new StringBuilder(input.Length);
        foreach (var c in input)
        {
            sb.AppendFormat("{0:x2}", Convert.ToUInt32(c));
        }

        return sb.ToString();
    }

    public static string DecodeFromHex(this string hexValue)
    {
        var strValue = string.Empty;
        while (hexValue.Length > 0)
        {
            strValue += Convert.ToChar(Convert.ToUInt32(hexValue[..2], 16)).ToString();
            hexValue = hexValue[2..];
        }

        return strValue;
    }

    /// <summary>
    ///     Encodes a string to a safe URL base64 string
    /// </summary>
    /// <param name="input"></param>
    /// <returns></returns>
    public static string ToUrlBase64(this string input)
    {
        if (input == null)
        {
            throw new ArgumentNullException(nameof(input));
        }

        if (string.IsNullOrEmpty(input))
        {
            return string.Empty;
        }

        // return Convert.ToBase64String(bytes).Replace(".", "-").Replace("/", "_").Replace("=", ",");
        var bytes = Encoding.UTF8.GetBytes(input);
        return UrlTokenEncode(bytes);
    }

    /// <summary>
    ///     Decodes a URL safe base64 string back
    /// </summary>
    /// <param name="input"></param>
    /// <returns></returns>
    public static string? FromUrlBase64(this string input)
    {
        if (input == null)
        {
            throw new ArgumentNullException(nameof(input));
        }

        // if (input.IsInvalidBase64()) return null;
        try
        {
            // var decodedBytes = Convert.FromBase64String(input.Replace("-", ".").Replace("_", "/").Replace(",", "="));
            var decodedBytes = UrlTokenDecode(input);
            return decodedBytes != null ? Encoding.UTF8.GetString(decodedBytes) : null;
        }
        catch (FormatException)
        {
            return null;
        }
    }

    /// <summary>
    ///     formats the string with invariant culture
    /// </summary>
    /// <param name="format">The format.</param>
    /// <param name="args">The args.</param>
    /// <returns></returns>
    public static string InvariantFormat(this string? format, params object?[] args) =>
        string.Format(CultureInfo.InvariantCulture, format ?? string.Empty, args);

    /// <summary>
    ///     Converts an integer to an invariant formatted string
    /// </summary>
    /// <param name="str"></param>
    /// <returns></returns>
    public static string ToInvariantString(this int str) => str.ToString(CultureInfo.InvariantCulture);

    public static string ToInvariantString(this long str) => str.ToString(CultureInfo.InvariantCulture);

    /// <summary>
    ///     Compares 2 strings with invariant culture and case ignored
    /// </summary>
    /// <param name="compare">The compare.</param>
    /// <param name="compareTo">The compare to.</param>
    /// <returns></returns>
    public static bool InvariantEquals(this string? compare, string? compareTo) =>
        string.Equals(compare, compareTo, StringComparison.InvariantCultureIgnoreCase);

    public static bool InvariantStartsWith(this string compare, string compareTo) =>
        compare.StartsWith(compareTo, StringComparison.InvariantCultureIgnoreCase);

    public static bool InvariantEndsWith(this string compare, string compareTo) =>
        compare.EndsWith(compareTo, StringComparison.InvariantCultureIgnoreCase);

    public static bool InvariantContains(this string compare, string compareTo) =>
        compare.Contains(compareTo, StringComparison.OrdinalIgnoreCase);

    public static bool InvariantContains(this IEnumerable<string> compare, string compareTo) =>
        compare.Contains(compareTo, StringComparer.InvariantCultureIgnoreCase);

    public static int InvariantIndexOf(this string s, string value) =>
        s.IndexOf(value, StringComparison.OrdinalIgnoreCase);

    public static int InvariantLastIndexOf(this string s, string value) =>
        s.LastIndexOf(value, StringComparison.OrdinalIgnoreCase);

    /// <summary>
    ///     Tries to parse a string into the supplied type by finding and using the Type's "Parse" method
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="val"></param>
    /// <returns></returns>
    public static T? ParseInto<T>(this string val) => (T?)val.ParseInto(typeof(T));

    /// <summary>
    ///     Tries to parse a string into the supplied type by finding and using the Type's "Parse" method
    /// </summary>
    /// <param name="val"></param>
    /// <param name="type"></param>
    /// <returns></returns>
    public static object? ParseInto(this string val, Type type)
    {
        if (string.IsNullOrEmpty(val) == false)
        {
            TypeConverter tc = TypeDescriptor.GetConverter(type);
            return tc.ConvertFrom(val);
        }

        return val;
    }

    /// <summary>
    ///     Generates a hash of a string based on the FIPS compliance setting.
    /// </summary>
    /// <param name="str">Refers to itself</param>
    /// <returns>The hashed string</returns>
    public static string GenerateHash(this string str) => str.ToSHA1();

    /// <summary>
    ///     Generate a hash of a string based on the specified hash algorithm.
    /// </summary>
    /// <typeparam name="T">The hash algorithm implementation to use.</typeparam>
    /// <param name="str">The <see cref="string" /> to hash.</param>
    /// <returns>
    ///     The hashed string.
    /// </returns>
    public static string GenerateHash<T>(this string str)
        where T : HashAlgorithm => str.GenerateHash(typeof(T).FullName);

    /// <summary>
    ///     Converts the string to SHA1
    /// </summary>
    /// <param name="stringToConvert">refers to itself</param>
    /// <returns>The SHA1 hashed string</returns>
    public static string ToSHA1(this string stringToConvert) => stringToConvert.GenerateHash("SHA1");

    /// <summary>
    ///     Decodes a string that was encoded with UrlTokenEncode
    /// </summary>
    /// <param name="input"></param>
    /// <returns></returns>
    public static byte[] UrlTokenDecode(this string input)
    {
        if (input == null)
        {
            throw new ArgumentNullException(nameof(input));
        }

        if (input.Length == 0)
        {
            return [];
        }

        // calc array size - must be groups of 4
        var arrayLength = input.Length;
        var remain = arrayLength % 4;
        if (remain != 0)
        {
            arrayLength += 4 - remain;
        }

        var inArray = new char[arrayLength];
        for (var i = 0; i < input.Length; i++)
        {
            var ch = input[i];
            switch (ch)
            {
                case '-': // restore '-' as '+'
                    inArray[i] = '+';
                    break;

                case '_': // restore '_' as '/'
                    inArray[i] = '/';
                    break;

                default: // keep char unchanged
                    inArray[i] = ch;
                    break;
            }
        }

        // pad with '='
        for (var j = input.Length; j < inArray.Length; j++)
        {
            inArray[j] = '=';
        }

        return Convert.FromBase64CharArray(inArray, 0, inArray.Length);
    }

    /// <summary>
    ///     Generate a hash of a string based on the hashType passed in
    /// </summary>
    /// <param name="str">Refers to itself</param>
    /// <param name="hashType">
    ///     String with the hash type.  See remarks section of the CryptoConfig Class in MSDN docs for a
    ///     list of possible values.
    /// </param>
    /// <returns>The hashed string</returns>
    private static string GenerateHash(this string str, string? hashType)
    {
        HashAlgorithm? hasher = null;

        // create an instance of the correct hashing provider based on the type passed in
        if (hashType is not null)
        {
            hasher = HashAlgorithm.Create(hashType);
        }

        if (hasher == null)
        {
            throw new InvalidOperationException("No hashing type found by name " + hashType);
        }

        using (hasher)
        {
            // convert our string into byte array
            var byteArray = Encoding.UTF8.GetBytes(str);

            // get the hashed values created by our selected provider
            var hashedByteArray = hasher.ComputeHash(byteArray);

            // create a StringBuilder object
            var stringBuilder = new StringBuilder();

            // loop to each byte
            foreach (var b in hashedByteArray)
            {
                // append it to our StringBuilder
                stringBuilder.Append(b.ToString("x2"));
            }

            // return the hashed value
            return stringBuilder.ToString();
        }
    }

    /// <summary>
    ///     Encodes a string so that it is 'safe' for URLs, files, etc..
    /// </summary>
    /// <param name="input"></param>
    /// <returns></returns>
    public static string UrlTokenEncode(this byte[] input)
    {
        if (input == null)
        {
            throw new ArgumentNullException(nameof(input));
        }

        if (input.Length == 0)
        {
            return string.Empty;
        }

        // base-64 digits are A-Z, a-z, 0-9, + and /
        // the = char is used for trailing padding
        var str = Convert.ToBase64String(input);

        var pos = str.IndexOf('=');
        if (pos < 0)
        {
            pos = str.Length;
        }

        // replace chars that would cause problems in URLs
        Span<char> chArray = pos <= 1024 ? stackalloc char[pos] : new char[pos];
        for (var i = 0; i < pos; i++)
        {
            var ch = str[i];
            switch (ch)
            {
                case '+': // replace '+' with '-'
                    chArray[i] = '-';
                    break;

                case '/': // replace '/' with '_'
                    chArray[i] = '_';
                    break;

                default: // keep char unchanged
                    chArray[i] = ch;
                    break;
            }
        }

        return new string(chArray);
    }

    /// <summary>
    ///     Ensures that the folder path ends with a DirectorySeparatorChar
    /// </summary>
    /// <param name="currentFolder"></param>
    /// <returns></returns>
    public static string NormaliseDirectoryPath(this string currentFolder)
    {
        currentFolder = currentFolder
            .IfNull(x => string.Empty)
            .TrimEnd(Path.DirectorySeparatorChar) + Path.DirectorySeparatorChar;
        return currentFolder;
    }

    /// <summary>
    ///     Truncates the specified text string.
    /// </summary>
    /// <param name="text">The text.</param>
    /// <param name="maxLength">Length of the max.</param>
    /// <param name="suffix">The suffix.</param>
    /// <returns></returns>
    public static string Truncate(this string text, int maxLength, string suffix = "...")
    {
        // replaces the truncated string to a ...
        var truncatedString = text;

        if (maxLength <= 0)
        {
            return truncatedString;
        }

        var strLength = maxLength - suffix.Length;

        if (strLength <= 0)
        {
            return truncatedString;
        }

        if (text == null || text.Length <= maxLength)
        {
            return truncatedString;
        }

        truncatedString = text[..strLength];
        truncatedString = truncatedString.TrimEnd();
        truncatedString += suffix;

        return truncatedString;
    }

    /// <summary>
    ///     Strips carrage returns and line feeds from the specified text.
    /// </summary>
    /// <param name="input">The input.</param>
    /// <returns></returns>
    public static string StripNewLines(this string input) => input.Replace("\r", string.Empty).Replace("\n", string.Empty);

    /// <summary>
    ///     Converts to single line by replacing line breaks with spaces.
    /// </summary>
    public static string ToSingleLine(this string text)
    {
        if (string.IsNullOrEmpty(text))
        {
            return text;
        }

        text = text.Replace("\r\n", " "); // remove CRLF
        text = text.Replace("\r", " "); // remove CR
        text = text.Replace("\n", " "); // remove LF
        return text;
    }

    public static string OrIfNullOrWhiteSpace(this string input, string alternative) =>
        !string.IsNullOrWhiteSpace(input)
            ? input
            : alternative;

    /// <summary>
    ///     Returns a copy of the string with the first character converted to uppercase.
    /// </summary>
    /// <param name="input">The string.</param>
    /// <returns>The converted string.</returns>
    public static string ToFirstUpper(this string input) =>
        string.IsNullOrWhiteSpace(input)
            ? input
            : input[..1].ToUpper() + input[1..];

    /// <summary>
    ///     Returns a copy of the string with the first character converted to lowercase.
    /// </summary>
    /// <param name="input">The string.</param>
    /// <returns>The converted string.</returns>
    public static string ToFirstLower(this string input) =>
        string.IsNullOrWhiteSpace(input)
            ? input
            : input[..1].ToLower() + input[1..];

    /// <summary>
    ///     Returns a copy of the string with the first character converted to uppercase using the casing rules of the
    ///     specified culture.
    /// </summary>
    /// <param name="input">The string.</param>
    /// <param name="culture">The culture.</param>
    /// <returns>The converted string.</returns>
    public static string ToFirstUpper(this string input, CultureInfo culture) =>
        string.IsNullOrWhiteSpace(input)
            ? input
            : input[..1].ToUpper(culture) + input[1..];

    /// <summary>
    ///     Returns a copy of the string with the first character converted to lowercase using the casing rules of the
    ///     specified culture.
    /// </summary>
    /// <param name="input">The string.</param>
    /// <param name="culture">The culture.</param>
    /// <returns>The converted string.</returns>
    public static string ToFirstLower(this string input, CultureInfo culture) =>
        string.IsNullOrWhiteSpace(input)
            ? input
            : input[..1].ToLower(culture) + input[1..];

    /// <summary>
    ///     Returns a copy of the string with the first character converted to uppercase using the casing rules of the
    ///     invariant culture.
    /// </summary>
    /// <param name="input">The string.</param>
    /// <returns>The converted string.</returns>
    public static string ToFirstUpperInvariant(this string input) =>
        string.IsNullOrWhiteSpace(input)
            ? input
            : input[..1].ToUpperInvariant() + input[1..];

    /// <summary>
    ///     Returns a copy of the string with the first character converted to lowercase using the casing rules of the
    ///     invariant culture.
    /// </summary>
    /// <param name="input">The string.</param>
    /// <returns>The converted string.</returns>
    public static string ToFirstLowerInvariant(this string input) =>
        string.IsNullOrWhiteSpace(input)
            ? input
            : input[..1].ToLowerInvariant() + input[1..];

    /// <summary>
    ///     Returns a new string in which all occurrences of specified strings are replaced by other specified strings.
    /// </summary>
    /// <param name="text">The string to filter.</param>
    /// <param name="replacements">The replacements definition.</param>
    /// <returns>The filtered string.</returns>
    public static string ReplaceMany(this string text, IDictionary<string, string> replacements)
    {
        if (text == null)
        {
            throw new ArgumentNullException(nameof(text));
        }

        if (replacements == null)
        {
            throw new ArgumentNullException(nameof(replacements));
        }

        foreach (KeyValuePair<string, string> item in replacements)
        {
            text = text.Replace(item.Key, item.Value);
        }

        return text;
    }

    /// <summary>
    ///     Returns a new string in which all occurrences of specified characters are replaced by a specified character.
    /// </summary>
    /// <param name="text">The string to filter.</param>
    /// <param name="chars">The characters to replace.</param>
    /// <param name="replacement">The replacement character.</param>
    /// <returns>The filtered string.</returns>
    public static string ReplaceMany(this string text, char[] chars, char replacement)
    {
        if (text == null)
        {
            throw new ArgumentNullException(nameof(text));
        }

        if (chars == null)
        {
            throw new ArgumentNullException(nameof(chars));
        }

        for (var i = 0; i < chars.Length; i++)
        {
            text = text.Replace(chars[i], replacement);
        }

        return text;
    }

    /// <summary>
    ///     Returns a new string in which only the first occurrence of a specified string is replaced by a specified
    ///     replacement string.
    /// </summary>
    /// <param name="text">The string to filter.</param>
    /// <param name="search">The string to replace.</param>
    /// <param name="replace">The replacement string.</param>
    /// <returns>The filtered string.</returns>
    public static string ReplaceFirst(this string text, string search, string replace)
    {
        if (text == null)
        {
            throw new ArgumentNullException(nameof(text));
        }

        ReadOnlySpan<char> spanText = text.AsSpan();
        var pos = spanText.IndexOf(search, StringComparison.InvariantCulture);

        if (pos < 0)
        {
            return text;
        }

        return string.Concat(spanText[..pos], replace.AsSpan(), spanText[(pos + search.Length)..]);
    }

    /// <summary>
    ///     An extension method that returns a new string in which all occurrences of a
    ///     specified string in the current instance are replaced with another specified string.
    ///     StringComparison specifies the type of search to use for the specified string.
    /// </summary>
    /// <param name="source">Current instance of the string</param>
    /// <param name="oldString">Specified string to replace</param>
    /// <param name="newString">Specified string to inject</param>
    /// <param name="stringComparison">String Comparison object to specify search type</param>
    /// <returns>Updated string</returns>
    public static string Replace(this string source, string oldString, string newString, StringComparison stringComparison)
    {
        // This initialization ensures the first check starts at index zero of the source. On successive checks for
        // a match, the source is skipped to immediately after the last replaced occurrence for efficiency
        // and to avoid infinite loops when oldString and newString compare equal.
        var index = -1 * newString.Length;

        // Determine if there are any matches left in source, starting from just after the result of replacing the last match.
        while ((index = source.IndexOf(oldString, index + newString.Length, stringComparison)) >= 0)
        {
            // Remove the old text.
            source = source.Remove(index, oldString.Length);

            // Add the replacement text.
            source = source.Insert(index, newString);
        }

        return source;
    }

    /// <summary>
    ///     Converts a literal string into a C# expression.
    /// </summary>
    /// <param name="s">Current instance of the string.</param>
    /// <returns>The string in a C# format.</returns>
    public static string ToCSharpString(this string s)
    {
        if (s == null)
        {
            return "<null>";
        }

        // http://stackoverflow.com/questions/323640/can-i-convert-a-c-sharp-string-value-to-an-escaped-string-literal
        var sb = new StringBuilder(s.Length + 2);
        for (var rp = 0; rp < s.Length; rp++)
        {
            var c = s[rp];
            if (c < ToCSharpEscapeChars.Length && ToCSharpEscapeChars[c] != '\0')
            {
                sb.Append('\\').Append(ToCSharpEscapeChars[c]);
            }
            else if (c <= '~' && c >= ' ')
            {
                sb.Append(c);
            }
            else
            {
                sb.Append(@"\x")
                    .Append(ToCSharpHexDigitLower[(c >> 12) & 0x0F])
                    .Append(ToCSharpHexDigitLower[(c >> 8) & 0x0F])
                    .Append(ToCSharpHexDigitLower[(c >> 4) & 0x0F])
                    .Append(ToCSharpHexDigitLower[c & 0x0F]);
            }
        }

        return sb.ToString();

        // requires full trust
        /*
        using (var writer = new StringWriter())
        using (var provider = CodeDomProvider.CreateProvider("CSharp"))
        {
            provider.GenerateCodeFromExpression(new CodePrimitiveExpression(s), writer, null);
            return writer.ToString().Replace(string.Format("\" +{0}\t\"", Environment.NewLine), "");
        }
        */
    }

    public static string EscapeRegexSpecialCharacters(this string text)
    {
        var regexSpecialCharacters = new Dictionary<string, string>
        {
            { ".", @"\." },
            { "(", @"\(" },
            { ")", @"\)" },
            { "]", @"\]" },
            { "[", @"\[" },
            { "{", @"\{" },
            { "}", @"\}" },
            { "?", @"\?" },
            { "!", @"\!" },
            { "$", @"\$" },
            { "^", @"\^" },
            { "+", @"\+" },
            { "*", @"\*" },
            { "|", @"\|" },
            { "<", @"\<" },
            { ">", @"\>" },
        };
        return ReplaceMany(text, regexSpecialCharacters);
    }

    /// <summary>
    ///     Checks whether a string "haystack" contains within it any of the strings in the "needles" collection and returns
    ///     true if it does or false if it doesn't
    /// </summary>
    /// <param name="haystack">The string to check</param>
    /// <param name="needles">The collection of strings to check are contained within the first string</param>
    /// <param name="comparison">
    ///     The type of comparison to perform - defaults to <see cref="StringComparison.CurrentCulture" />
    /// </param>
    /// <returns>True if any of the needles are contained with haystack; otherwise returns false</returns>
    /// Added fix to ensure the comparison is used - see http://issues.umbraco.org/issue/U4-11313
    public static bool ContainsAny(this string haystack, IEnumerable<string> needles, StringComparison comparison = StringComparison.CurrentCulture)
    {
        if (haystack == null)
        {
            throw new ArgumentNullException("haystack");
        }

        if (string.IsNullOrEmpty(haystack) || needles == null || !needles.Any())
        {
            return false;
        }

        return needles.Any(value => haystack.IndexOf(value, comparison) >= 0);
    }

    public static bool CsvContains(this string csv, string value)
    {
        if (string.IsNullOrEmpty(csv))
        {
            return false;
        }

        var idCheckList = csv.Split(Constants.CharArrays.Comma, StringSplitOptions.RemoveEmptyEntries);
        return idCheckList.Contains(value);
    }

    /// <summary>
    ///     Converts a file name to a friendly name for a content item
    /// </summary>
    /// <param name="fileName"></param>
    /// <returns></returns>
    public static string ToFriendlyName(this string fileName)
    {
        // strip the file extension
        fileName = fileName.StripFileExtension();

        // underscores and dashes to spaces
        fileName = fileName.ReplaceMany(Constants.CharArrays.UnderscoreDash, ' ');

        // any other conversions ?

        // Pascalcase (to be done last)
        fileName = CultureInfo.InvariantCulture.TextInfo.ToTitleCase(fileName);

        // Replace multiple consecutive spaces with a single space
        fileName = string.Join(" ", fileName.Split(Constants.CharArrays.Space, StringSplitOptions.RemoveEmptyEntries));

        return fileName;
    }

    /// <summary>
    ///     An extension method that returns a new string in which all occurrences of an
    ///     unicode characters that are invalid in XML files are replaced with an empty string.
    /// </summary>
    /// <param name="text">Current instance of the string</param>
    /// <returns>Updated string</returns>
    /// <summary>
    ///     removes any unusual unicode characters that can't be encoded into XML
    /// </summary>
    public static string ToValidXmlString(this string text) =>
        string.IsNullOrEmpty(text) ? text : InvalidXmlChars.Value.Replace(text, string.Empty);

    /// <summary>
    ///     Converts a string to a Guid - WARNING, depending on the string, this may not be unique
    /// </summary>
    /// <param name="text"></param>
    /// <returns></returns>
    public static Guid ToGuid(this string text) =>
        CreateGuidFromHash(
            UrlNamespace,
            text,
            CryptoConfig.AllowOnlyFipsAlgorithms ? 5 // SHA1
                : 3); // MD5

    /// <summary>
    ///     Turns an null-or-whitespace string into a null string.
    /// </summary>
    public static string? NullOrWhiteSpaceAsNull(this string? text)
        => string.IsNullOrWhiteSpace(text) ? null : text;

    /// <summary>
    ///     Creates a name-based UUID using the algorithm from RFC 4122 §4.3.
    ///     See
    ///     <a href="https://github.com/LogosBible/Logos.Utility/blob/master/src/Logos.Utility/GuidUtility.cs#L34">GuidUtility.cs</a>
    ///     for original implementation.
    /// </summary>
    /// <param name="namespaceId">The ID of the namespace.</param>
    /// <param name="name">The name (within that namespace).</param>
    /// <param name="version">
    ///     The version number of the UUID to create; this value must be either
    ///     3 (for MD5 hashing) or 5 (for SHA-1 hashing).
    /// </param>
    /// <returns>A UUID derived from the namespace and name.</returns>
    /// <remarks>
    ///     See
    ///     <a href="http://code.logos.com/blog/2011/04/generating_a_deterministic_guid.html">Generating a deterministic GUID</a>
    ///     .
    /// </remarks>
    internal static Guid CreateGuidFromHash(Guid namespaceId, string name, int version)
    {
        if (name == null)
        {
            throw new ArgumentNullException("name");
        }

        if (version != 3 && version != 5)
        {
            throw new ArgumentOutOfRangeException("version", "version must be either 3 or 5.");
        }

        // convert the name to a sequence of octets (as defined by the standard or conventions of its namespace) (step 3)
        // ASSUME: UTF-8 encoding is always appropriate
        var nameBytes = Encoding.UTF8.GetBytes(name);

        // convert the namespace UUID to network order (step 3)
        var namespaceBytes = namespaceId.ToByteArray();
        SwapByteOrder(namespaceBytes);

        // comput the hash of the name space ID concatenated with the name (step 4)
        byte[] hash;
        using (HashAlgorithm algorithm = version == 3 ? MD5.Create() : SHA1.Create())
        {
            algorithm.TransformBlock(namespaceBytes, 0, namespaceBytes.Length, null, 0);
            algorithm.TransformFinalBlock(nameBytes, 0, nameBytes.Length);
            hash = algorithm.Hash!;
        }

        // most bytes from the hash are copied straight to the bytes of the new GUID (steps 5-7, 9, 11-12)
        Span<byte> newGuid = hash.AsSpan()[..16];

        // set the four most significant bits (bits 12 through 15) of the time_hi_and_version field to the appropriate 4-bit version number from Section 4.1.3 (step 8)
        newGuid[6] = (byte)((newGuid[6] & 0x0F) | (version << 4));

        // set the two most significant bits (bits 6 and 7) of the clock_seq_hi_and_reserved to zero and one, respectively (step 10)
        newGuid[8] = (byte)((newGuid[8] & 0x3F) | 0x80);

        // convert the resulting UUID to local byte order (step 13)
        SwapByteOrder(newGuid);
        return new Guid(newGuid);
    }

    // Converts a GUID (expressed as a byte array) to/from network order (MSB-first).
    internal static void SwapByteOrder(Span<byte> guid)
    {
        SwapBytes(guid, 0, 3);
        SwapBytes(guid, 1, 2);
        SwapBytes(guid, 4, 5);
        SwapBytes(guid, 6, 7);
    }

    private static void SwapBytes(Span<byte> guid, int left, int right) => (guid[left], guid[right]) = (guid[right], guid[left]);

    /// <summary>
    ///     Checks if a given path is a full path including drive letter
    /// </summary>
    /// <param name="path"></param>
    /// <returns></returns>
    public static bool IsFullPath(this string path) => Path.IsPathFullyQualified(path);

    // FORMAT STRINGS

    /// <summary>
    ///     Cleans a string to produce a string that can safely be used in an alias.
    /// </summary>
    /// <param name="alias">The text to filter.</param>
    /// <param name="shortStringHelper">The short string helper.</param>
    /// <returns>The safe alias.</returns>
    public static string ToSafeAlias(this string alias, IShortStringHelper? shortStringHelper) =>
        shortStringHelper?.CleanStringForSafeAlias(alias) ?? string.Empty;

    /// <summary>
    ///     Cleans a string to produce a string that can safely be used in an alias.
    /// </summary>
    /// <param name="alias">The text to filter.</param>
    /// <param name="camel">A value indicating that we want to camel-case the alias.</param>
    /// <param name="shortStringHelper">The short string helper.</param>
    /// <returns>The safe alias.</returns>
    public static string ToSafeAlias(this string alias, IShortStringHelper shortStringHelper, bool camel)
    {
        var a = shortStringHelper.CleanStringForSafeAlias(alias);
        if (string.IsNullOrWhiteSpace(a) || camel == false)
        {
            return a;
        }

        return char.ToLowerInvariant(a[0]) + a[1..];
    }

    /// <summary>
    ///     Cleans a string, in the context of a specified culture, to produce a string that can safely be used in an alias.
    /// </summary>
    /// <param name="alias">The text to filter.</param>
    /// <param name="culture">The culture.</param>
    /// <param name="shortStringHelper">The short string helper.</param>
    /// <returns>The safe alias.</returns>
    public static string ToSafeAlias(this string alias, IShortStringHelper shortStringHelper, string culture) =>
        shortStringHelper.CleanStringForSafeAlias(alias, culture);

    // the new methods to get a url segment

    /// <summary>
    ///     Cleans a string to produce a string that can safely be used in an url segment.
    /// </summary>
    /// <param name="text">The text to filter.</param>
    /// <param name="shortStringHelper">The short string helper.</param>
    /// <returns>The safe url segment.</returns>
    public static string ToUrlSegment(this string text, IShortStringHelper shortStringHelper)
    {
        if (text == null)
        {
            throw new ArgumentNullException(nameof(text));
        }

        if (string.IsNullOrWhiteSpace(text))
        {
            throw new ArgumentException(
                "Value can't be empty or consist only of white-space characters.",
                nameof(text));
        }

        return shortStringHelper.CleanStringForUrlSegment(text);
    }

    /// <summary>
    ///     Cleans a string, in the context of a specified culture, to produce a string that can safely be used in an url
    ///     segment.
    /// </summary>
    /// <param name="text">The text to filter.</param>
    /// <param name="shortStringHelper">The short string helper.</param>
    /// <param name="culture">The culture.</param>
    /// <returns>The safe url segment.</returns>
    public static string ToUrlSegment(this string text, IShortStringHelper shortStringHelper, string? culture)
    {
        if (text == null)
        {
            throw new ArgumentNullException(nameof(text));
        }

        if (string.IsNullOrWhiteSpace(text))
        {
            throw new ArgumentException(
                "Value can't be empty or consist only of white-space characters.",
                nameof(text));
        }

        return shortStringHelper.CleanStringForUrlSegment(text, culture);
    }

    /// <summary>
    ///     Cleans a string.
    /// </summary>
    /// <param name="text">The text to clean.</param>
    /// <param name="shortStringHelper">The short string helper.</param>
    /// <param name="stringType">
    ///     A flag indicating the target casing and encoding of the string. By default,
    ///     strings are cleaned up to camelCase and Ascii.
    /// </param>
    /// <returns>The clean string.</returns>
    /// <remarks>The string is cleaned in the context of the ICurrent.ShortStringHelper default culture.</remarks>
    public static string ToCleanString(this string text, IShortStringHelper shortStringHelper, CleanStringType stringType) => shortStringHelper.CleanString(text, stringType);

    /// <summary>
    ///     Cleans a string, using a specified separator.
    /// </summary>
    /// <param name="text">The text to clean.</param>
    /// <param name="shortStringHelper">The short string helper.</param>
    /// <param name="stringType">
    ///     A flag indicating the target casing and encoding of the string. By default,
    ///     strings are cleaned up to camelCase and Ascii.
    /// </param>
    /// <param name="separator">The separator.</param>
    /// <returns>The clean string.</returns>
    /// <remarks>The string is cleaned in the context of the ICurrent.ShortStringHelper default culture.</remarks>
    public static string ToCleanString(this string text, IShortStringHelper shortStringHelper, CleanStringType stringType, char separator) => shortStringHelper.CleanString(text, stringType, separator);

    /// <summary>
    ///     Cleans a string in the context of a specified culture.
    /// </summary>
    /// <param name="text">The text to clean.</param>
    /// <param name="shortStringHelper">The short string helper.</param>
    /// <param name="stringType">
    ///     A flag indicating the target casing and encoding of the string. By default,
    ///     strings are cleaned up to camelCase and Ascii.
    /// </param>
    /// <param name="culture">The culture.</param>
    /// <returns>The clean string.</returns>
    public static string ToCleanString(this string text, IShortStringHelper shortStringHelper, CleanStringType stringType, string culture) => shortStringHelper.CleanString(text, stringType, culture);

    /// <summary>
    ///     Cleans a string in the context of a specified culture, using a specified separator.
    /// </summary>
    /// <param name="text">The text to clean.</param>
    /// <param name="shortStringHelper">The short string helper.</param>
    /// <param name="stringType">
    ///     A flag indicating the target casing and encoding of the string. By default,
    ///     strings are cleaned up to camelCase and Ascii.
    /// </param>
    /// <param name="separator">The separator.</param>
    /// <param name="culture">The culture.</param>
    /// <returns>The clean string.</returns>
    public static string ToCleanString(this string text, IShortStringHelper shortStringHelper, CleanStringType stringType, char separator, string culture) =>
        shortStringHelper.CleanString(text, stringType, separator, culture);

    // note: LegacyCurrent.ShortStringHelper will produce 100% backward-compatible output for SplitPascalCasing.
    // other helpers may not. DefaultCurrent.ShortStringHelper produces better, but non-compatible, results.

    /// <summary>
    ///     Splits a Pascal cased string into a phrase separated by spaces.
    /// </summary>
    /// <param name="phrase">The text to split.</param>
    /// <param name="shortStringHelper"></param>
    /// <returns>The split text.</returns>
    public static string SplitPascalCasing(this string phrase, IShortStringHelper shortStringHelper) =>
        shortStringHelper.SplitPascalCasing(phrase, ' ');

    /// <summary>
    ///     Cleans a string, in the context of the invariant culture, to produce a string that can safely be used as a
    ///     filename,
    ///     both internally (on disk) and externally (as a url).
    /// </summary>
    /// <param name="text">The text to filter.</param>
    /// <param name="shortStringHelper"></param>
    /// <returns>The safe filename.</returns>
    public static string ToSafeFileName(this string text, IShortStringHelper shortStringHelper) =>
        shortStringHelper.CleanStringForSafeFileName(text);

    // NOTE: Not sure what this actually does but is used a few places, need to figure it out and then move to StringExtensions and obsolete.
    // it basically is yet another version of SplitPascalCasing
    // plugging string extensions here to be 99% compatible
    // the only diff. is with numbers, Number6Is was "Number6 Is", and the new string helper does it too,
    // but the legacy one does "Number6Is"... assuming it is not a big deal.
    internal static string SpaceCamelCasing(this string phrase, IShortStringHelper shortStringHelper) =>
        phrase.Length < 2 ? phrase : phrase.SplitPascalCasing(shortStringHelper).ToFirstUpperInvariant();

    /// <summary>
    ///     Cleans a string, in the context of the invariant culture, to produce a string that can safely be used as a
    ///     filename,
    ///     both internally (on disk) and externally (as a url).
    /// </summary>
    /// <param name="text">The text to filter.</param>
    /// <param name="shortStringHelper"></param>
    /// <param name="culture">The culture.</param>
    /// <returns>The safe filename.</returns>
    public static string ToSafeFileName(this string text, IShortStringHelper shortStringHelper, string culture) =>
        shortStringHelper.CleanStringForSafeFileName(text, culture);

    /// <summary>
    ///     Splits a string with an escape character that allows for the split character to exist in a string
    /// </summary>
    /// <param name="value">The string to split</param>
    /// <param name="splitChar">The character to split on</param>
    /// <param name="escapeChar">The character which can be used to escape the character to split on</param>
    /// <returns>The string split into substrings delimited by the split character</returns>
    public static IEnumerable<string> EscapedSplit(this string value, char splitChar, char escapeChar = DefaultEscapedStringEscapeChar)
    {
        if (value == null)
        {
            yield break;
        }

        var sb = new StringBuilder(value.Length);
        var escaped = false;

        foreach (var chr in value.ToCharArray())
        {
            if (escaped)
            {
                escaped = false;
                sb.Append(chr);
            }
            else if (chr == splitChar)
            {
                yield return sb.ToString();
                sb.Clear();
            }
            else if (chr == escapeChar)
            {
                escaped = true;
            }
            else
            {
                sb.Append(chr);
            }
        }

        yield return sb.ToString();
    }

    /// <summary>
    ///     Checks whether a string is a valid email address.
    /// </summary>
    /// <param name="email">The string check</param>
    /// <returns>Returns a bool indicating whether the string is an email address.</returns>
    public static bool IsEmail(this string? email) =>
        string.IsNullOrWhiteSpace(email) is false && new EmailAddressAttribute().IsValid(email);

    // having benchmarked various solutions (incl. for/foreach, split and LINQ based ones),
    // this is by far the fastest way to find string needles in a string haystack
    public static int CountOccurrences(this string haystack, string needle)
        => haystack.Length - haystack.Replace(needle, string.Empty).Length;

    /// <summary>
    /// Verifies the provided string is a valid culture code and returns it in a consistent casing.
    /// </summary>
    /// <param name="culture">Culture code.</param>
    /// <returns>Culture code in standard casing.</returns>
    public static string? EnsureCultureCode(this string? culture)
    {
        if (string.IsNullOrEmpty(culture) || culture == "*")
        {
            return culture;
        }

        // Create as CultureInfo instance from provided name so we can ensure consistent casing of culture code when persisting.
        // This will accept mixed case but once created have a `Name` property that is consistently and correctly cased.
        // Will throw in an invalid culture code is provided.
        return new CultureInfo(culture).Name;
    }
}
